1 /* 2 * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang; 27 28 import java.lang.annotation.Native; 29 import java.math.*; 30 import java.util.Objects; 31 import jdk.internal.HotSpotIntrinsicCandidate; 32 33 import static java.lang.String.COMPACT_STRINGS; 34 import static java.lang.String.LATIN1; 35 import static java.lang.String.UTF16; 36 37 /** 38 * The {@code Long} class wraps a value of the primitive type {@code 39 * long} in an object. An object of type {@code Long} contains a 40 * single field whose type is {@code long}. 41 * 42 * <p> In addition, this class provides several methods for converting 43 * a {@code long} to a {@code String} and a {@code String} to a {@code 44 * long}, as well as other constants and methods useful when dealing 45 * with a {@code long}. 46 * 47 * <p>Implementation note: The implementations of the "bit twiddling" 48 * methods (such as {@link #highestOneBit(long) highestOneBit} and 49 * {@link #numberOfTrailingZeros(long) numberOfTrailingZeros}) are 50 * based on material from Henry S. Warren, Jr.'s <i>Hacker's 51 * Delight</i>, (Addison Wesley, 2002). 52 * 53 * @author Lee Boynton 54 * @author Arthur van Hoff 55 * @author Josh Bloch 56 * @author Joseph D. Darcy 57 * @since 1.0 58 */ 59 public final class Long extends Number implements Comparable<Long> { 60 /** 61 * A constant holding the minimum value a {@code long} can 62 * have, -2<sup>63</sup>. 63 */ 64 @Native public static final long MIN_VALUE = 0x8000000000000000L; 65 66 /** 67 * A constant holding the maximum value a {@code long} can 68 * have, 2<sup>63</sup>-1. 69 */ 70 @Native public static final long MAX_VALUE = 0x7fffffffffffffffL; 71 72 /** 73 * The {@code Class} instance representing the primitive type 74 * {@code long}. 75 * 76 * @since 1.1 77 */ 78 @SuppressWarnings("unchecked") 79 public static final Class<Long> TYPE = (Class<Long>) Class.getPrimitiveClass("long"); 80 81 /** 82 * Returns a string representation of the first argument in the 83 * radix specified by the second argument. 84 * 85 * <p>If the radix is smaller than {@code Character.MIN_RADIX} 86 * or larger than {@code Character.MAX_RADIX}, then the radix 87 * {@code 10} is used instead. 88 * 89 * <p>If the first argument is negative, the first element of the 90 * result is the ASCII minus sign {@code '-'} 91 * ({@code '\u005Cu002d'}). If the first argument is not 92 * negative, no sign character appears in the result. 93 * 94 * <p>The remaining characters of the result represent the magnitude 95 * of the first argument. If the magnitude is zero, it is 96 * represented by a single zero character {@code '0'} 97 * ({@code '\u005Cu0030'}); otherwise, the first character of 98 * the representation of the magnitude will not be the zero 99 * character. The following ASCII characters are used as digits: 100 * 101 * <blockquote> 102 * {@code 0123456789abcdefghijklmnopqrstuvwxyz} 103 * </blockquote> 104 * 105 * These are {@code '\u005Cu0030'} through 106 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through 107 * {@code '\u005Cu007a'}. If {@code radix} is 108 * <var>N</var>, then the first <var>N</var> of these characters 109 * are used as radix-<var>N</var> digits in the order shown. Thus, 110 * the digits for hexadecimal (radix 16) are 111 * {@code 0123456789abcdef}. If uppercase letters are 112 * desired, the {@link java.lang.String#toUpperCase()} method may 113 * be called on the result: 114 * 115 * <blockquote> 116 * {@code Long.toString(n, 16).toUpperCase()} 117 * </blockquote> 118 * 119 * @param i a {@code long} to be converted to a string. 120 * @param radix the radix to use in the string representation. 121 * @return a string representation of the argument in the specified radix. 122 * @see java.lang.Character#MAX_RADIX 123 * @see java.lang.Character#MIN_RADIX 124 */ 125 public static String toString(long i, int radix) { 126 if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) 127 radix = 10; 128 if (radix == 10) 129 return toString(i); 130 131 if (COMPACT_STRINGS) { 132 byte[] buf = new byte[65]; 133 int charPos = 64; 134 boolean negative = (i < 0); 135 136 if (!negative) { 137 i = -i; 138 } 139 140 while (i <= -radix) { 141 buf[charPos--] = (byte)Integer.digits[(int)(-(i % radix))]; 142 i = i / radix; 143 } 144 buf[charPos] = (byte)Integer.digits[(int)(-i)]; 145 146 if (negative) { 147 buf[--charPos] = '-'; 148 } 149 return StringLatin1.newString(buf, charPos, (65 - charPos)); 150 } 151 return toStringUTF16(i, radix); 152 } 153 154 private static String toStringUTF16(long i, int radix) { 155 byte[] buf = new byte[65 * 2]; 156 int charPos = 64; 157 boolean negative = (i < 0); 158 if (!negative) { 159 i = -i; 160 } 161 while (i <= -radix) { 162 StringUTF16.putChar(buf, charPos--, Integer.digits[(int)(-(i % radix))]); 163 i = i / radix; 164 } 165 StringUTF16.putChar(buf, charPos, Integer.digits[(int)(-i)]); 166 if (negative) { 167 StringUTF16.putChar(buf, --charPos, '-'); 168 } 169 return StringUTF16.newString(buf, charPos, (65 - charPos)); 170 } 171 172 /** 173 * Returns a string representation of the first argument as an 174 * unsigned integer value in the radix specified by the second 175 * argument. 176 * 177 * <p>If the radix is smaller than {@code Character.MIN_RADIX} 178 * or larger than {@code Character.MAX_RADIX}, then the radix 179 * {@code 10} is used instead. 180 * 181 * <p>Note that since the first argument is treated as an unsigned 182 * value, no leading sign character is printed. 183 * 184 * <p>If the magnitude is zero, it is represented by a single zero 185 * character {@code '0'} ({@code '\u005Cu0030'}); otherwise, 186 * the first character of the representation of the magnitude will 187 * not be the zero character. 188 * 189 * <p>The behavior of radixes and the characters used as digits 190 * are the same as {@link #toString(long, int) toString}. 191 * 192 * @param i an integer to be converted to an unsigned string. 193 * @param radix the radix to use in the string representation. 194 * @return an unsigned string representation of the argument in the specified radix. 195 * @see #toString(long, int) 196 * @since 1.8 197 */ 198 public static String toUnsignedString(long i, int radix) { 199 if (i >= 0) 200 return toString(i, radix); 201 else { 202 switch (radix) { 203 case 2: 204 return toBinaryString(i); 205 206 case 4: 207 return toUnsignedString0(i, 2); 208 209 case 8: 210 return toOctalString(i); 211 212 case 10: 213 /* 214 * We can get the effect of an unsigned division by 10 215 * on a long value by first shifting right, yielding a 216 * positive value, and then dividing by 5. This 217 * allows the last digit and preceding digits to be 218 * isolated more quickly than by an initial conversion 219 * to BigInteger. 220 */ 221 long quot = (i >>> 1) / 5; 222 long rem = i - quot * 10; 223 return toString(quot) + rem; 224 225 case 16: 226 return toHexString(i); 227 228 case 32: 229 return toUnsignedString0(i, 5); 230 231 default: 232 return toUnsignedBigInteger(i).toString(radix); 233 } 234 } 235 } 236 237 /** 238 * Return a BigInteger equal to the unsigned value of the 239 * argument. 240 */ 241 private static BigInteger toUnsignedBigInteger(long i) { 242 if (i >= 0L) 243 return BigInteger.valueOf(i); 244 else { 245 int upper = (int) (i >>> 32); 246 int lower = (int) i; 247 248 // return (upper << 32) + lower 249 return (BigInteger.valueOf(Integer.toUnsignedLong(upper))).shiftLeft(32). 250 add(BigInteger.valueOf(Integer.toUnsignedLong(lower))); 251 } 252 } 253 254 /** 255 * Returns a string representation of the {@code long} 256 * argument as an unsigned integer in base 16. 257 * 258 * <p>The unsigned {@code long} value is the argument plus 259 * 2<sup>64</sup> if the argument is negative; otherwise, it is 260 * equal to the argument. This value is converted to a string of 261 * ASCII digits in hexadecimal (base 16) with no extra 262 * leading {@code 0}s. 263 * 264 * <p>The value of the argument can be recovered from the returned 265 * string {@code s} by calling {@link 266 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 267 * 16)}. 268 * 269 * <p>If the unsigned magnitude is zero, it is represented by a 270 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 271 * otherwise, the first character of the representation of the 272 * unsigned magnitude will not be the zero character. The 273 * following characters are used as hexadecimal digits: 274 * 275 * <blockquote> 276 * {@code 0123456789abcdef} 277 * </blockquote> 278 * 279 * These are the characters {@code '\u005Cu0030'} through 280 * {@code '\u005Cu0039'} and {@code '\u005Cu0061'} through 281 * {@code '\u005Cu0066'}. If uppercase letters are desired, 282 * the {@link java.lang.String#toUpperCase()} method may be called 283 * on the result: 284 * 285 * <blockquote> 286 * {@code Long.toHexString(n).toUpperCase()} 287 * </blockquote> 288 * 289 * @param i a {@code long} to be converted to a string. 290 * @return the string representation of the unsigned {@code long} 291 * value represented by the argument in hexadecimal 292 * (base 16). 293 * @see #parseUnsignedLong(String, int) 294 * @see #toUnsignedString(long, int) 295 * @since 1.0.2 296 */ 297 public static String toHexString(long i) { 298 return toUnsignedString0(i, 4); 299 } 300 301 /** 302 * Returns a string representation of the {@code long} 303 * argument as an unsigned integer in base 8. 304 * 305 * <p>The unsigned {@code long} value is the argument plus 306 * 2<sup>64</sup> if the argument is negative; otherwise, it is 307 * equal to the argument. This value is converted to a string of 308 * ASCII digits in octal (base 8) with no extra leading 309 * {@code 0}s. 310 * 311 * <p>The value of the argument can be recovered from the returned 312 * string {@code s} by calling {@link 313 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 314 * 8)}. 315 * 316 * <p>If the unsigned magnitude is zero, it is represented by a 317 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 318 * otherwise, the first character of the representation of the 319 * unsigned magnitude will not be the zero character. The 320 * following characters are used as octal digits: 321 * 322 * <blockquote> 323 * {@code 01234567} 324 * </blockquote> 325 * 326 * These are the characters {@code '\u005Cu0030'} through 327 * {@code '\u005Cu0037'}. 328 * 329 * @param i a {@code long} to be converted to a string. 330 * @return the string representation of the unsigned {@code long} 331 * value represented by the argument in octal (base 8). 332 * @see #parseUnsignedLong(String, int) 333 * @see #toUnsignedString(long, int) 334 * @since 1.0.2 335 */ 336 public static String toOctalString(long i) { 337 return toUnsignedString0(i, 3); 338 } 339 340 /** 341 * Returns a string representation of the {@code long} 342 * argument as an unsigned integer in base 2. 343 * 344 * <p>The unsigned {@code long} value is the argument plus 345 * 2<sup>64</sup> if the argument is negative; otherwise, it is 346 * equal to the argument. This value is converted to a string of 347 * ASCII digits in binary (base 2) with no extra leading 348 * {@code 0}s. 349 * 350 * <p>The value of the argument can be recovered from the returned 351 * string {@code s} by calling {@link 352 * Long#parseUnsignedLong(String, int) Long.parseUnsignedLong(s, 353 * 2)}. 354 * 355 * <p>If the unsigned magnitude is zero, it is represented by a 356 * single zero character {@code '0'} ({@code '\u005Cu0030'}); 357 * otherwise, the first character of the representation of the 358 * unsigned magnitude will not be the zero character. The 359 * characters {@code '0'} ({@code '\u005Cu0030'}) and {@code 360 * '1'} ({@code '\u005Cu0031'}) are used as binary digits. 361 * 362 * @param i a {@code long} to be converted to a string. 363 * @return the string representation of the unsigned {@code long} 364 * value represented by the argument in binary (base 2). 365 * @see #parseUnsignedLong(String, int) 366 * @see #toUnsignedString(long, int) 367 * @since 1.0.2 368 */ 369 public static String toBinaryString(long i) { 370 return toUnsignedString0(i, 1); 371 } 372 373 /** 374 * Format a long (treated as unsigned) into a String. 375 * @param val the value to format 376 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 377 */ 378 static String toUnsignedString0(long val, int shift) { 379 // assert shift > 0 && shift <=5 : "Illegal shift value"; 380 int mag = Long.SIZE - Long.numberOfLeadingZeros(val); 381 int chars = Math.max(((mag + (shift - 1)) / shift), 1); 382 if (COMPACT_STRINGS) { 383 byte[] buf = new byte[chars]; 384 formatUnsignedLong0(val, shift, buf, 0, chars); 385 return new String(buf, LATIN1); 386 } else { 387 byte[] buf = new byte[chars * 2]; 388 formatUnsignedLong0UTF16(val, shift, buf, 0, chars); 389 return new String(buf, UTF16); 390 } 391 } 392 393 /** 394 * Format a long (treated as unsigned) into a character buffer. If 395 * {@code len} exceeds the formatted ASCII representation of {@code val}, 396 * {@code buf} will be padded with leading zeroes. 397 * 398 * @param val the unsigned long to format 399 * @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary) 400 * @param buf the character buffer to write to 401 * @param offset the offset in the destination buffer to start at 402 * @param len the number of characters to write 403 */ 404 405 /** byte[]/LATIN1 version */ 406 static void formatUnsignedLong0(long val, int shift, byte[] buf, int offset, int len) { 407 int charPos = offset + len; 408 int radix = 1 << shift; 409 int mask = radix - 1; 410 do { 411 buf[--charPos] = (byte)Integer.digits[((int) val) & mask]; 412 val >>>= shift; 413 } while (charPos > offset); 414 } 415 416 /** byte[]/UTF16 version */ 417 private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) { 418 int charPos = offset + len; 419 int radix = 1 << shift; 420 int mask = radix - 1; 421 do { 422 StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]); 423 val >>>= shift; 424 } while (charPos > offset); 425 } 426 427 static String fastUUID(long lsb, long msb) { 428 if (COMPACT_STRINGS) { 429 byte[] buf = new byte[36]; 430 formatUnsignedLong0(lsb, 4, buf, 24, 12); 431 formatUnsignedLong0(lsb >>> 48, 4, buf, 19, 4); 432 formatUnsignedLong0(msb, 4, buf, 14, 4); 433 formatUnsignedLong0(msb >>> 16, 4, buf, 9, 4); 434 formatUnsignedLong0(msb >>> 32, 4, buf, 0, 8); 435 436 buf[23] = '-'; 437 buf[18] = '-'; 438 buf[13] = '-'; 439 buf[8] = '-'; 440 441 return new String(buf, LATIN1); 442 } else { 443 byte[] buf = new byte[72]; 444 445 formatUnsignedLong0UTF16(lsb, 4, buf, 24, 12); 446 formatUnsignedLong0UTF16(lsb >>> 48, 4, buf, 19, 4); 447 formatUnsignedLong0UTF16(msb, 4, buf, 14, 4); 448 formatUnsignedLong0UTF16(msb >>> 16, 4, buf, 9, 4); 449 formatUnsignedLong0UTF16(msb >>> 32, 4, buf, 0, 8); 450 451 StringUTF16.putChar(buf, 23, '-'); 452 StringUTF16.putChar(buf, 18, '-'); 453 StringUTF16.putChar(buf, 13, '-'); 454 StringUTF16.putChar(buf, 8, '-'); 455 456 return new String(buf, UTF16); 457 } 458 } 459 460 /** 461 * Returns a {@code String} object representing the specified 462 * {@code long}. The argument is converted to signed decimal 463 * representation and returned as a string, exactly as if the 464 * argument and the radix 10 were given as arguments to the {@link 465 * #toString(long, int)} method. 466 * 467 * @param i a {@code long} to be converted. 468 * @return a string representation of the argument in base 10. 469 */ 470 public static String toString(long i) { 471 int size = stringSize(i); 472 if (COMPACT_STRINGS) { 473 byte[] buf = new byte[size]; 474 getChars(i, size, buf); 475 return new String(buf, LATIN1); 476 } else { 477 byte[] buf = new byte[size * 2]; 478 StringUTF16.getChars(i, size, buf); 479 return new String(buf, UTF16); 480 } 481 } 482 483 /** 484 * Returns a string representation of the argument as an unsigned 485 * decimal value. 486 * 487 * The argument is converted to unsigned decimal representation 488 * and returned as a string exactly as if the argument and radix 489 * 10 were given as arguments to the {@link #toUnsignedString(long, 490 * int)} method. 491 * 492 * @param i an integer to be converted to an unsigned string. 493 * @return an unsigned string representation of the argument. 494 * @see #toUnsignedString(long, int) 495 * @since 1.8 496 */ 497 public static String toUnsignedString(long i) { 498 return toUnsignedString(i, 10); 499 } 500 501 /** 502 * Places characters representing the long i into the 503 * character array buf. The characters are placed into 504 * the buffer backwards starting with the least significant 505 * digit at the specified index (exclusive), and working 506 * backwards from there. 507 * 508 * @implNote This method converts positive inputs into negative 509 * values, to cover the Long.MIN_VALUE case. Converting otherwise 510 * (negative to positive) will expose -Long.MIN_VALUE that overflows 511 * long. 512 * 513 * @param i value to convert 514 * @param index next index, after the least significant digit 515 * @param buf target buffer, Latin1-encoded 516 * @return index of the most significant digit or minus sign, if present 517 */ 518 static int getChars(long i, int index, byte[] buf) { 519 long q; 520 int r; 521 int charPos = index; 522 523 boolean negative = (i < 0); 524 if (!negative) { 525 i = -i; 526 } 527 528 // Get 2 digits/iteration using longs until quotient fits into an int 529 while (i <= Integer.MIN_VALUE) { 530 q = i / 100; 531 r = (int)((q * 100) - i); 532 i = q; 533 buf[--charPos] = Integer.DigitOnes[r]; 534 buf[--charPos] = Integer.DigitTens[r]; 535 } 536 537 // Get 2 digits/iteration using ints 538 int q2; 539 int i2 = (int)i; 540 while (i2 <= -100) { 541 q2 = i2 / 100; 542 r = (q2 * 100) - i2; 543 i2 = q2; 544 buf[--charPos] = Integer.DigitOnes[r]; 545 buf[--charPos] = Integer.DigitTens[r]; 546 } 547 548 // We know there are at most two digits left at this point. 549 q2 = i2 / 10; 550 r = (q2 * 10) - i2; 551 buf[--charPos] = (byte)('0' + r); 552 553 // Whatever left is the remaining digit. 554 if (q2 < 0) { 555 buf[--charPos] = (byte)('0' - q2); 556 } 557 558 if (negative) { 559 buf[--charPos] = (byte)'-'; 560 } 561 return charPos; 562 } 563 564 /** 565 * Returns the string representation size for a given long value. 566 * 567 * @param x long value 568 * @return string size 569 * 570 * @implNote There are other ways to compute this: e.g. binary search, 571 * but values are biased heavily towards zero, and therefore linear search 572 * wins. The iteration results are also routinely inlined in the generated 573 * code after loop unrolling. 574 */ 575 static int stringSize(long x) { 576 int d = 1; 577 if (x >= 0) { 578 d = 0; 579 x = -x; 580 } 581 long p = -10; 582 for (int i = 1; i < 19; i++) { 583 if (x > p) 584 return i + d; 585 p = 10 * p; 586 } 587 return 19 + d; 588 } 589 590 /** 591 * Parses the string argument as a signed {@code long} in the 592 * radix specified by the second argument. The characters in the 593 * string must all be digits of the specified radix (as determined 594 * by whether {@link java.lang.Character#digit(char, int)} returns 595 * a nonnegative value), except that the first character may be an 596 * ASCII minus sign {@code '-'} ({@code '\u005Cu002D'}) to 597 * indicate a negative value or an ASCII plus sign {@code '+'} 598 * ({@code '\u005Cu002B'}) to indicate a positive value. The 599 * resulting {@code long} value is returned. 600 * 601 * <p>Note that neither the character {@code L} 602 * ({@code '\u005Cu004C'}) nor {@code l} 603 * ({@code '\u005Cu006C'}) is permitted to appear at the end 604 * of the string as a type indicator, as would be permitted in 605 * Java programming language source code - except that either 606 * {@code L} or {@code l} may appear as a digit for a 607 * radix greater than or equal to 22. 608 * 609 * <p>An exception of type {@code NumberFormatException} is 610 * thrown if any of the following situations occurs: 611 * <ul> 612 * 613 * <li>The first argument is {@code null} or is a string of 614 * length zero. 615 * 616 * <li>The {@code radix} is either smaller than {@link 617 * java.lang.Character#MIN_RADIX} or larger than {@link 618 * java.lang.Character#MAX_RADIX}. 619 * 620 * <li>Any character of the string is not a digit of the specified 621 * radix, except that the first character may be a minus sign 622 * {@code '-'} ({@code '\u005Cu002d'}) or plus sign {@code 623 * '+'} ({@code '\u005Cu002B'}) provided that the string is 624 * longer than length 1. 625 * 626 * <li>The value represented by the string is not a value of type 627 * {@code long}. 628 * </ul> 629 * 630 * <p>Examples: 631 * <blockquote><pre> 632 * parseLong("0", 10) returns 0L 633 * parseLong("473", 10) returns 473L 634 * parseLong("+42", 10) returns 42L 635 * parseLong("-0", 10) returns 0L 636 * parseLong("-FF", 16) returns -255L 637 * parseLong("1100110", 2) returns 102L 638 * parseLong("99", 8) throws a NumberFormatException 639 * parseLong("Hazelnut", 10) throws a NumberFormatException 640 * parseLong("Hazelnut", 36) returns 1356099454469L 641 * </pre></blockquote> 642 * 643 * @param s the {@code String} containing the 644 * {@code long} representation to be parsed. 645 * @param radix the radix to be used while parsing {@code s}. 646 * @return the {@code long} represented by the string argument in 647 * the specified radix. 648 * @throws NumberFormatException if the string does not contain a 649 * parsable {@code long}. 650 */ 651 public static long parseLong(String s, int radix) 652 throws NumberFormatException 653 { 654 if (s == null) { 655 throw new NumberFormatException("null"); 656 } 657 658 if (radix < Character.MIN_RADIX) { 659 throw new NumberFormatException("radix " + radix + 660 " less than Character.MIN_RADIX"); 661 } 662 if (radix > Character.MAX_RADIX) { 663 throw new NumberFormatException("radix " + radix + 664 " greater than Character.MAX_RADIX"); 665 } 666 667 boolean negative = false; 668 int i = 0, len = s.length(); 669 long limit = -Long.MAX_VALUE; 670 671 if (len > 0) { 672 char firstChar = s.charAt(0); 673 if (firstChar < '0') { // Possible leading "+" or "-" 674 if (firstChar == '-') { 675 negative = true; 676 limit = Long.MIN_VALUE; 677 } else if (firstChar != '+') { 678 throw NumberFormatException.forInputString(s); 679 } 680 681 if (len == 1) { // Cannot have lone "+" or "-" 682 throw NumberFormatException.forInputString(s); 683 } 684 i++; 685 } 686 long multmin = limit / radix; 687 long result = 0; 688 while (i < len) { 689 // Accumulating negatively avoids surprises near MAX_VALUE 690 int digit = Character.digit(s.charAt(i++),radix); 691 if (digit < 0 || result < multmin) { 692 throw NumberFormatException.forInputString(s); 693 } 694 result *= radix; 695 if (result < limit + digit) { 696 throw NumberFormatException.forInputString(s); 697 } 698 result -= digit; 699 } 700 return negative ? result : -result; 701 } else { 702 throw NumberFormatException.forInputString(s); 703 } 704 } 705 706 /** 707 * Parses the {@link CharSequence} argument as a signed {@code long} in 708 * the specified {@code radix}, beginning at the specified 709 * {@code beginIndex} and extending to {@code endIndex - 1}. 710 * 711 * <p>The method does not take steps to guard against the 712 * {@code CharSequence} being mutated while parsing. 713 * 714 * @param s the {@code CharSequence} containing the {@code long} 715 * representation to be parsed 716 * @param beginIndex the beginning index, inclusive. 717 * @param endIndex the ending index, exclusive. 718 * @param radix the radix to be used while parsing {@code s}. 719 * @return the signed {@code long} represented by the subsequence in 720 * the specified radix. 721 * @throws NullPointerException if {@code s} is null. 722 * @throws IndexOutOfBoundsException if {@code beginIndex} is 723 * negative, or if {@code beginIndex} is greater than 724 * {@code endIndex} or if {@code endIndex} is greater than 725 * {@code s.length()}. 726 * @throws NumberFormatException if the {@code CharSequence} does not 727 * contain a parsable {@code int} in the specified 728 * {@code radix}, or if {@code radix} is either smaller than 729 * {@link java.lang.Character#MIN_RADIX} or larger than 730 * {@link java.lang.Character#MAX_RADIX}. 731 * @since 9 732 */ 733 public static long parseLong(CharSequence s, int beginIndex, int endIndex, int radix) 734 throws NumberFormatException { 735 s = Objects.requireNonNull(s); 736 737 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { 738 throw new IndexOutOfBoundsException(); 739 } 740 if (radix < Character.MIN_RADIX) { 741 throw new NumberFormatException("radix " + radix + 742 " less than Character.MIN_RADIX"); 743 } 744 if (radix > Character.MAX_RADIX) { 745 throw new NumberFormatException("radix " + radix + 746 " greater than Character.MAX_RADIX"); 747 } 748 749 boolean negative = false; 750 int i = beginIndex; 751 long limit = -Long.MAX_VALUE; 752 753 if (i < endIndex) { 754 char firstChar = s.charAt(i); 755 if (firstChar < '0') { // Possible leading "+" or "-" 756 if (firstChar == '-') { 757 negative = true; 758 limit = Long.MIN_VALUE; 759 } else if (firstChar != '+') { 760 throw NumberFormatException.forCharSequence(s, beginIndex, 761 endIndex, i); 762 } 763 i++; 764 } 765 if (i >= endIndex) { // Cannot have lone "+", "-" or "" 766 throw NumberFormatException.forCharSequence(s, beginIndex, 767 endIndex, i); 768 } 769 long multmin = limit / radix; 770 long result = 0; 771 while (i < endIndex) { 772 // Accumulating negatively avoids surprises near MAX_VALUE 773 int digit = Character.digit(s.charAt(i), radix); 774 if (digit < 0 || result < multmin) { 775 throw NumberFormatException.forCharSequence(s, beginIndex, 776 endIndex, i); 777 } 778 result *= radix; 779 if (result < limit + digit) { 780 throw NumberFormatException.forCharSequence(s, beginIndex, 781 endIndex, i); 782 } 783 i++; 784 result -= digit; 785 } 786 return negative ? result : -result; 787 } else { 788 throw new NumberFormatException(""); 789 } 790 } 791 792 /** 793 * Parses the string argument as a signed decimal {@code long}. 794 * The characters in the string must all be decimal digits, except 795 * that the first character may be an ASCII minus sign {@code '-'} 796 * ({@code \u005Cu002D'}) to indicate a negative value or an 797 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to 798 * indicate a positive value. The resulting {@code long} value is 799 * returned, exactly as if the argument and the radix {@code 10} 800 * were given as arguments to the {@link 801 * #parseLong(java.lang.String, int)} method. 802 * 803 * <p>Note that neither the character {@code L} 804 * ({@code '\u005Cu004C'}) nor {@code l} 805 * ({@code '\u005Cu006C'}) is permitted to appear at the end 806 * of the string as a type indicator, as would be permitted in 807 * Java programming language source code. 808 * 809 * @param s a {@code String} containing the {@code long} 810 * representation to be parsed 811 * @return the {@code long} represented by the argument in 812 * decimal. 813 * @throws NumberFormatException if the string does not contain a 814 * parsable {@code long}. 815 */ 816 public static long parseLong(String s) throws NumberFormatException { 817 return parseLong(s, 10); 818 } 819 820 /** 821 * Parses the string argument as an unsigned {@code long} in the 822 * radix specified by the second argument. An unsigned integer 823 * maps the values usually associated with negative numbers to 824 * positive numbers larger than {@code MAX_VALUE}. 825 * 826 * The characters in the string must all be digits of the 827 * specified radix (as determined by whether {@link 828 * java.lang.Character#digit(char, int)} returns a nonnegative 829 * value), except that the first character may be an ASCII plus 830 * sign {@code '+'} ({@code '\u005Cu002B'}). The resulting 831 * integer value is returned. 832 * 833 * <p>An exception of type {@code NumberFormatException} is 834 * thrown if any of the following situations occurs: 835 * <ul> 836 * <li>The first argument is {@code null} or is a string of 837 * length zero. 838 * 839 * <li>The radix is either smaller than 840 * {@link java.lang.Character#MIN_RADIX} or 841 * larger than {@link java.lang.Character#MAX_RADIX}. 842 * 843 * <li>Any character of the string is not a digit of the specified 844 * radix, except that the first character may be a plus sign 845 * {@code '+'} ({@code '\u005Cu002B'}) provided that the 846 * string is longer than length 1. 847 * 848 * <li>The value represented by the string is larger than the 849 * largest unsigned {@code long}, 2<sup>64</sup>-1. 850 * 851 * </ul> 852 * 853 * 854 * @param s the {@code String} containing the unsigned integer 855 * representation to be parsed 856 * @param radix the radix to be used while parsing {@code s}. 857 * @return the unsigned {@code long} represented by the string 858 * argument in the specified radix. 859 * @throws NumberFormatException if the {@code String} 860 * does not contain a parsable {@code long}. 861 * @since 1.8 862 */ 863 public static long parseUnsignedLong(String s, int radix) 864 throws NumberFormatException { 865 if (s == null) { 866 throw new NumberFormatException("null"); 867 } 868 869 int len = s.length(); 870 if (len > 0) { 871 char firstChar = s.charAt(0); 872 if (firstChar == '-') { 873 throw new 874 NumberFormatException(String.format("Illegal leading minus sign " + 875 "on unsigned string %s.", s)); 876 } else { 877 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits 878 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits 879 return parseLong(s, radix); 880 } 881 882 // No need for range checks on len due to testing above. 883 long first = parseLong(s, 0, len - 1, radix); 884 int second = Character.digit(s.charAt(len - 1), radix); 885 if (second < 0) { 886 throw new NumberFormatException("Bad digit at end of " + s); 887 } 888 long result = first * radix + second; 889 890 /* 891 * Test leftmost bits of multiprecision extension of first*radix 892 * for overflow. The number of bits needed is defined by 893 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then 894 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and 895 * overflow is tested by splitting guard in the ranges 896 * guard < 92, 92 <= guard < 128, and 128 <= guard, where 897 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take 898 * on a value which does not include a prime factor in the legal 899 * radix range. 900 */ 901 int guard = radix * (int) (first >>> 57); 902 if (guard >= 128 || 903 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) { 904 /* 905 * For purposes of exposition, the programmatic statements 906 * below should be taken to be multi-precision, i.e., not 907 * subject to overflow. 908 * 909 * A) Condition guard >= 128: 910 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 911 * hence always overflow. 912 * 913 * B) Condition guard < 92: 914 * Define left7 = first >>> 57. 915 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then 916 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. 917 * Thus if radix*left7 < 92, radix <= 36, and second < 36, 918 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence 919 * never overflow. 920 * 921 * C) Condition 92 <= guard < 128: 922 * first*radix + second >= radix*left7*2^57 + second 923 * so that first*radix + second >= 92*2^57 + 0 > 2^63 924 * 925 * D) Condition guard < 128: 926 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) 927 * so 928 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 929 * thus 930 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 931 * whence 932 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 933 * 934 * E) Conditions C, D, and result >= 0: 935 * C and D combined imply the mathematical result 936 * 2^63 < first*radix + second < 2^64 + 2^63. The lower 937 * bound is therefore negative as a signed long, but the 938 * upper bound is too small to overflow again after the 939 * signed long overflows to positive above 2^64 - 1. Hence 940 * result >= 0 implies overflow given C and D. 941 */ 942 throw new NumberFormatException(String.format("String value %s exceeds " + 943 "range of unsigned long.", s)); 944 } 945 return result; 946 } 947 } else { 948 throw NumberFormatException.forInputString(s); 949 } 950 } 951 952 /** 953 * Parses the {@link CharSequence} argument as an unsigned {@code long} in 954 * the specified {@code radix}, beginning at the specified 955 * {@code beginIndex} and extending to {@code endIndex - 1}. 956 * 957 * <p>The method does not take steps to guard against the 958 * {@code CharSequence} being mutated while parsing. 959 * 960 * @param s the {@code CharSequence} containing the unsigned 961 * {@code long} representation to be parsed 962 * @param beginIndex the beginning index, inclusive. 963 * @param endIndex the ending index, exclusive. 964 * @param radix the radix to be used while parsing {@code s}. 965 * @return the unsigned {@code long} represented by the subsequence in 966 * the specified radix. 967 * @throws NullPointerException if {@code s} is null. 968 * @throws IndexOutOfBoundsException if {@code beginIndex} is 969 * negative, or if {@code beginIndex} is greater than 970 * {@code endIndex} or if {@code endIndex} is greater than 971 * {@code s.length()}. 972 * @throws NumberFormatException if the {@code CharSequence} does not 973 * contain a parsable unsigned {@code long} in the specified 974 * {@code radix}, or if {@code radix} is either smaller than 975 * {@link java.lang.Character#MIN_RADIX} or larger than 976 * {@link java.lang.Character#MAX_RADIX}. 977 * @since 9 978 */ 979 public static long parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix) 980 throws NumberFormatException { 981 s = Objects.requireNonNull(s); 982 983 if (beginIndex < 0 || beginIndex > endIndex || endIndex > s.length()) { 984 throw new IndexOutOfBoundsException(); 985 } 986 int start = beginIndex, len = endIndex - beginIndex; 987 988 if (len > 0) { 989 char firstChar = s.charAt(start); 990 if (firstChar == '-') { 991 throw new NumberFormatException(String.format("Illegal leading minus sign " + 992 "on unsigned string %s.", s.subSequence(start, start + len))); 993 } else { 994 if (len <= 12 || // Long.MAX_VALUE in Character.MAX_RADIX is 13 digits 995 (radix == 10 && len <= 18) ) { // Long.MAX_VALUE in base 10 is 19 digits 996 return parseLong(s, start, start + len, radix); 997 } 998 999 // No need for range checks on end due to testing above. 1000 long first = parseLong(s, start, start + len - 1, radix); 1001 int second = Character.digit(s.charAt(start + len - 1), radix); 1002 if (second < 0) { 1003 throw new NumberFormatException("Bad digit at end of " + 1004 s.subSequence(start, start + len)); 1005 } 1006 long result = first * radix + second; 1007 1008 /* 1009 * Test leftmost bits of multiprecision extension of first*radix 1010 * for overflow. The number of bits needed is defined by 1011 * GUARD_BIT = ceil(log2(Character.MAX_RADIX)) + 1 = 7. Then 1012 * int guard = radix*(int)(first >>> (64 - GUARD_BIT)) and 1013 * overflow is tested by splitting guard in the ranges 1014 * guard < 92, 92 <= guard < 128, and 128 <= guard, where 1015 * 92 = 128 - Character.MAX_RADIX. Note that guard cannot take 1016 * on a value which does not include a prime factor in the legal 1017 * radix range. 1018 */ 1019 int guard = radix * (int) (first >>> 57); 1020 if (guard >= 128 || 1021 (result >= 0 && guard >= 128 - Character.MAX_RADIX)) { 1022 /* 1023 * For purposes of exposition, the programmatic statements 1024 * below should be taken to be multi-precision, i.e., not 1025 * subject to overflow. 1026 * 1027 * A) Condition guard >= 128: 1028 * If guard >= 128 then first*radix >= 2^7 * 2^57 = 2^64 1029 * hence always overflow. 1030 * 1031 * B) Condition guard < 92: 1032 * Define left7 = first >>> 57. 1033 * Given first = (left7 * 2^57) + (first & (2^57 - 1)) then 1034 * result <= (radix*left7)*2^57 + radix*(2^57 - 1) + second. 1035 * Thus if radix*left7 < 92, radix <= 36, and second < 36, 1036 * then result < 92*2^57 + 36*(2^57 - 1) + 36 = 2^64 hence 1037 * never overflow. 1038 * 1039 * C) Condition 92 <= guard < 128: 1040 * first*radix + second >= radix*left7*2^57 + second 1041 * so that first*radix + second >= 92*2^57 + 0 > 2^63 1042 * 1043 * D) Condition guard < 128: 1044 * radix*first <= (radix*left7) * 2^57 + radix*(2^57 - 1) 1045 * so 1046 * radix*first + second <= (radix*left7) * 2^57 + radix*(2^57 - 1) + 36 1047 * thus 1048 * radix*first + second < 128 * 2^57 + 36*2^57 - radix + 36 1049 * whence 1050 * radix*first + second < 2^64 + 2^6*2^57 = 2^64 + 2^63 1051 * 1052 * E) Conditions C, D, and result >= 0: 1053 * C and D combined imply the mathematical result 1054 * 2^63 < first*radix + second < 2^64 + 2^63. The lower 1055 * bound is therefore negative as a signed long, but the 1056 * upper bound is too small to overflow again after the 1057 * signed long overflows to positive above 2^64 - 1. Hence 1058 * result >= 0 implies overflow given C and D. 1059 */ 1060 throw new NumberFormatException(String.format("String value %s exceeds " + 1061 "range of unsigned long.", s.subSequence(start, start + len))); 1062 } 1063 return result; 1064 } 1065 } else { 1066 throw NumberFormatException.forInputString(""); 1067 } 1068 } 1069 1070 /** 1071 * Parses the string argument as an unsigned decimal {@code long}. The 1072 * characters in the string must all be decimal digits, except 1073 * that the first character may be an ASCII plus sign {@code 1074 * '+'} ({@code '\u005Cu002B'}). The resulting integer value 1075 * is returned, exactly as if the argument and the radix 10 were 1076 * given as arguments to the {@link 1077 * #parseUnsignedLong(java.lang.String, int)} method. 1078 * 1079 * @param s a {@code String} containing the unsigned {@code long} 1080 * representation to be parsed 1081 * @return the unsigned {@code long} value represented by the decimal string argument 1082 * @throws NumberFormatException if the string does not contain a 1083 * parsable unsigned integer. 1084 * @since 1.8 1085 */ 1086 public static long parseUnsignedLong(String s) throws NumberFormatException { 1087 return parseUnsignedLong(s, 10); 1088 } 1089 1090 /** 1091 * Returns a {@code Long} object holding the value 1092 * extracted from the specified {@code String} when parsed 1093 * with the radix given by the second argument. The first 1094 * argument is interpreted as representing a signed 1095 * {@code long} in the radix specified by the second 1096 * argument, exactly as if the arguments were given to the {@link 1097 * #parseLong(java.lang.String, int)} method. The result is a 1098 * {@code Long} object that represents the {@code long} 1099 * value specified by the string. 1100 * 1101 * <p>In other words, this method returns a {@code Long} object equal 1102 * to the value of: 1103 * 1104 * <blockquote> 1105 * {@code new Long(Long.parseLong(s, radix))} 1106 * </blockquote> 1107 * 1108 * @param s the string to be parsed 1109 * @param radix the radix to be used in interpreting {@code s} 1110 * @return a {@code Long} object holding the value 1111 * represented by the string argument in the specified 1112 * radix. 1113 * @throws NumberFormatException If the {@code String} does not 1114 * contain a parsable {@code long}. 1115 */ 1116 public static Long valueOf(String s, int radix) throws NumberFormatException { 1117 return Long.valueOf(parseLong(s, radix)); 1118 } 1119 1120 /** 1121 * Returns a {@code Long} object holding the value 1122 * of the specified {@code String}. The argument is 1123 * interpreted as representing a signed decimal {@code long}, 1124 * exactly as if the argument were given to the {@link 1125 * #parseLong(java.lang.String)} method. The result is a 1126 * {@code Long} object that represents the integer value 1127 * specified by the string. 1128 * 1129 * <p>In other words, this method returns a {@code Long} object 1130 * equal to the value of: 1131 * 1132 * <blockquote> 1133 * {@code new Long(Long.parseLong(s))} 1134 * </blockquote> 1135 * 1136 * @param s the string to be parsed. 1137 * @return a {@code Long} object holding the value 1138 * represented by the string argument. 1139 * @throws NumberFormatException If the string cannot be parsed 1140 * as a {@code long}. 1141 */ 1142 public static Long valueOf(String s) throws NumberFormatException 1143 { 1144 return Long.valueOf(parseLong(s, 10)); 1145 } 1146 1147 private static class LongCache { 1148 private LongCache(){} 1149 1150 static final Long cache[] = new Long[-(-128) + 127 + 1]; 1151 1152 static { 1153 for(int i = 0; i < cache.length; i++) 1154 cache[i] = new Long(i - 128); 1155 } 1156 } 1157 1158 /** 1159 * Returns a {@code Long} instance representing the specified 1160 * {@code long} value. 1161 * If a new {@code Long} instance is not required, this method 1162 * should generally be used in preference to the constructor 1163 * {@link #Long(long)}, as this method is likely to yield 1164 * significantly better space and time performance by caching 1165 * frequently requested values. 1166 * 1167 * This method will always cache values in the range -128 to 127, 1168 * inclusive, and may cache other values outside of this range. 1169 * 1170 * @param l a long value. 1171 * @return a {@code Long} instance representing {@code l}. 1172 * @since 1.5 1173 */ 1174 @HotSpotIntrinsicCandidate 1175 public static Long valueOf(long l) { 1176 final int offset = 128; 1177 if (l >= -128 && l <= 127) { // will cache 1178 return LongCache.cache[(int)l + offset]; 1179 } 1180 return new Long(l); 1181 } 1182 1183 /** 1184 * Decodes a {@code String} into a {@code Long}. 1185 * Accepts decimal, hexadecimal, and octal numbers given by the 1186 * following grammar: 1187 * 1188 * <blockquote> 1189 * <dl> 1190 * <dt><i>DecodableString:</i> 1191 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 1192 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 1193 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 1194 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 1195 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 1196 * 1197 * <dt><i>Sign:</i> 1198 * <dd>{@code -} 1199 * <dd>{@code +} 1200 * </dl> 1201 * </blockquote> 1202 * 1203 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 1204 * are as defined in section 3.10.1 of 1205 * <cite>The Java™ Language Specification</cite>, 1206 * except that underscores are not accepted between digits. 1207 * 1208 * <p>The sequence of characters following an optional 1209 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 1210 * "{@code #}", or leading zero) is parsed as by the {@code 1211 * Long.parseLong} method with the indicated radix (10, 16, or 8). 1212 * This sequence of characters must represent a positive value or 1213 * a {@link NumberFormatException} will be thrown. The result is 1214 * negated if first character of the specified {@code String} is 1215 * the minus sign. No whitespace characters are permitted in the 1216 * {@code String}. 1217 * 1218 * @param nm the {@code String} to decode. 1219 * @return a {@code Long} object holding the {@code long} 1220 * value represented by {@code nm} 1221 * @throws NumberFormatException if the {@code String} does not 1222 * contain a parsable {@code long}. 1223 * @see java.lang.Long#parseLong(String, int) 1224 * @since 1.2 1225 */ 1226 public static Long decode(String nm) throws NumberFormatException { 1227 int radix = 10; 1228 int index = 0; 1229 boolean negative = false; 1230 Long result; 1231 1232 if (nm.length() == 0) 1233 throw new NumberFormatException("Zero length string"); 1234 char firstChar = nm.charAt(0); 1235 // Handle sign, if present 1236 if (firstChar == '-') { 1237 negative = true; 1238 index++; 1239 } else if (firstChar == '+') 1240 index++; 1241 1242 // Handle radix specifier, if present 1243 if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) { 1244 index += 2; 1245 radix = 16; 1246 } 1247 else if (nm.startsWith("#", index)) { 1248 index ++; 1249 radix = 16; 1250 } 1251 else if (nm.startsWith("0", index) && nm.length() > 1 + index) { 1252 index ++; 1253 radix = 8; 1254 } 1255 1256 if (nm.startsWith("-", index) || nm.startsWith("+", index)) 1257 throw new NumberFormatException("Sign character in wrong position"); 1258 1259 try { 1260 result = Long.valueOf(nm.substring(index), radix); 1261 result = negative ? Long.valueOf(-result.longValue()) : result; 1262 } catch (NumberFormatException e) { 1263 // If number is Long.MIN_VALUE, we'll end up here. The next line 1264 // handles this case, and causes any genuine format error to be 1265 // rethrown. 1266 String constant = negative ? ("-" + nm.substring(index)) 1267 : nm.substring(index); 1268 result = Long.valueOf(constant, radix); 1269 } 1270 return result; 1271 } 1272 1273 /** 1274 * The value of the {@code Long}. 1275 * 1276 * @serial 1277 */ 1278 private final long value; 1279 1280 /** 1281 * Constructs a newly allocated {@code Long} object that 1282 * represents the specified {@code long} argument. 1283 * 1284 * @param value the value to be represented by the 1285 * {@code Long} object. 1286 * 1287 * @deprecated 1288 * It is rarely appropriate to use this constructor. The static factory 1289 * {@link #valueOf(long)} is generally a better choice, as it is 1290 * likely to yield significantly better space and time performance. 1291 */ 1292 @Deprecated(since="9") 1293 public Long(long value) { 1294 this.value = value; 1295 } 1296 1297 /** 1298 * Constructs a newly allocated {@code Long} object that 1299 * represents the {@code long} value indicated by the 1300 * {@code String} parameter. The string is converted to a 1301 * {@code long} value in exactly the manner used by the 1302 * {@code parseLong} method for radix 10. 1303 * 1304 * @param s the {@code String} to be converted to a 1305 * {@code Long}. 1306 * @throws NumberFormatException if the {@code String} does not 1307 * contain a parsable {@code long}. 1308 * 1309 * @deprecated 1310 * It is rarely appropriate to use this constructor. 1311 * Use {@link #parseLong(String)} to convert a string to a 1312 * {@code long} primitive, or use {@link #valueOf(String)} 1313 * to convert a string to a {@code Long} object. 1314 */ 1315 @Deprecated(since="9") 1316 public Long(String s) throws NumberFormatException { 1317 this.value = parseLong(s, 10); 1318 } 1319 1320 /** 1321 * Returns the value of this {@code Long} as a {@code byte} after 1322 * a narrowing primitive conversion. 1323 * @jls 5.1.3 Narrowing Primitive Conversions 1324 */ 1325 public byte byteValue() { 1326 return (byte)value; 1327 } 1328 1329 /** 1330 * Returns the value of this {@code Long} as a {@code short} after 1331 * a narrowing primitive conversion. 1332 * @jls 5.1.3 Narrowing Primitive Conversions 1333 */ 1334 public short shortValue() { 1335 return (short)value; 1336 } 1337 1338 /** 1339 * Returns the value of this {@code Long} as an {@code int} after 1340 * a narrowing primitive conversion. 1341 * @jls 5.1.3 Narrowing Primitive Conversions 1342 */ 1343 public int intValue() { 1344 return (int)value; 1345 } 1346 1347 /** 1348 * Returns the value of this {@code Long} as a 1349 * {@code long} value. 1350 */ 1351 @HotSpotIntrinsicCandidate 1352 public long longValue() { 1353 return value; 1354 } 1355 1356 /** 1357 * Returns the value of this {@code Long} as a {@code float} after 1358 * a widening primitive conversion. 1359 * @jls 5.1.2 Widening Primitive Conversions 1360 */ 1361 public float floatValue() { 1362 return (float)value; 1363 } 1364 1365 /** 1366 * Returns the value of this {@code Long} as a {@code double} 1367 * after a widening primitive conversion. 1368 * @jls 5.1.2 Widening Primitive Conversions 1369 */ 1370 public double doubleValue() { 1371 return (double)value; 1372 } 1373 1374 /** 1375 * Returns a {@code String} object representing this 1376 * {@code Long}'s value. The value is converted to signed 1377 * decimal representation and returned as a string, exactly as if 1378 * the {@code long} value were given as an argument to the 1379 * {@link java.lang.Long#toString(long)} method. 1380 * 1381 * @return a string representation of the value of this object in 1382 * base 10. 1383 */ 1384 public String toString() { 1385 return toString(value); 1386 } 1387 1388 /** 1389 * Returns a hash code for this {@code Long}. The result is 1390 * the exclusive OR of the two halves of the primitive 1391 * {@code long} value held by this {@code Long} 1392 * object. That is, the hashcode is the value of the expression: 1393 * 1394 * <blockquote> 1395 * {@code (int)(this.longValue()^(this.longValue()>>>32))} 1396 * </blockquote> 1397 * 1398 * @return a hash code value for this object. 1399 */ 1400 @Override 1401 public int hashCode() { 1402 return Long.hashCode(value); 1403 } 1404 1405 /** 1406 * Returns a hash code for a {@code long} value; compatible with 1407 * {@code Long.hashCode()}. 1408 * 1409 * @param value the value to hash 1410 * @return a hash code value for a {@code long} value. 1411 * @since 1.8 1412 */ 1413 public static int hashCode(long value) { 1414 return (int)(value ^ (value >>> 32)); 1415 } 1416 1417 /** 1418 * Compares this object to the specified object. The result is 1419 * {@code true} if and only if the argument is not 1420 * {@code null} and is a {@code Long} object that 1421 * contains the same {@code long} value as this object. 1422 * 1423 * @param obj the object to compare with. 1424 * @return {@code true} if the objects are the same; 1425 * {@code false} otherwise. 1426 */ 1427 public boolean equals(Object obj) { 1428 if (obj instanceof Long) { 1429 return value == ((Long)obj).longValue(); 1430 } 1431 return false; 1432 } 1433 1434 /** 1435 * Determines the {@code long} value of the system property 1436 * with the specified name. 1437 * 1438 * <p>The first argument is treated as the name of a system 1439 * property. System properties are accessible through the {@link 1440 * java.lang.System#getProperty(java.lang.String)} method. The 1441 * string value of this property is then interpreted as a {@code 1442 * long} value using the grammar supported by {@link Long#decode decode} 1443 * and a {@code Long} object representing this value is returned. 1444 * 1445 * <p>If there is no property with the specified name, if the 1446 * specified name is empty or {@code null}, or if the property 1447 * does not have the correct numeric format, then {@code null} is 1448 * returned. 1449 * 1450 * <p>In other words, this method returns a {@code Long} object 1451 * equal to the value of: 1452 * 1453 * <blockquote> 1454 * {@code getLong(nm, null)} 1455 * </blockquote> 1456 * 1457 * @param nm property name. 1458 * @return the {@code Long} value of the property. 1459 * @throws SecurityException for the same reasons as 1460 * {@link System#getProperty(String) System.getProperty} 1461 * @see java.lang.System#getProperty(java.lang.String) 1462 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1463 */ 1464 public static Long getLong(String nm) { 1465 return getLong(nm, null); 1466 } 1467 1468 /** 1469 * Determines the {@code long} value of the system property 1470 * with the specified name. 1471 * 1472 * <p>The first argument is treated as the name of a system 1473 * property. System properties are accessible through the {@link 1474 * java.lang.System#getProperty(java.lang.String)} method. The 1475 * string value of this property is then interpreted as a {@code 1476 * long} value using the grammar supported by {@link Long#decode decode} 1477 * and a {@code Long} object representing this value is returned. 1478 * 1479 * <p>The second argument is the default value. A {@code Long} object 1480 * that represents the value of the second argument is returned if there 1481 * is no property of the specified name, if the property does not have 1482 * the correct numeric format, or if the specified name is empty or null. 1483 * 1484 * <p>In other words, this method returns a {@code Long} object equal 1485 * to the value of: 1486 * 1487 * <blockquote> 1488 * {@code getLong(nm, new Long(val))} 1489 * </blockquote> 1490 * 1491 * but in practice it may be implemented in a manner such as: 1492 * 1493 * <blockquote><pre> 1494 * Long result = getLong(nm, null); 1495 * return (result == null) ? new Long(val) : result; 1496 * </pre></blockquote> 1497 * 1498 * to avoid the unnecessary allocation of a {@code Long} object when 1499 * the default value is not needed. 1500 * 1501 * @param nm property name. 1502 * @param val default value. 1503 * @return the {@code Long} value of the property. 1504 * @throws SecurityException for the same reasons as 1505 * {@link System#getProperty(String) System.getProperty} 1506 * @see java.lang.System#getProperty(java.lang.String) 1507 * @see java.lang.System#getProperty(java.lang.String, java.lang.String) 1508 */ 1509 public static Long getLong(String nm, long val) { 1510 Long result = Long.getLong(nm, null); 1511 return (result == null) ? Long.valueOf(val) : result; 1512 } 1513 1514 /** 1515 * Returns the {@code long} value of the system property with 1516 * the specified name. The first argument is treated as the name 1517 * of a system property. System properties are accessible through 1518 * the {@link java.lang.System#getProperty(java.lang.String)} 1519 * method. The string value of this property is then interpreted 1520 * as a {@code long} value, as per the 1521 * {@link Long#decode decode} method, and a {@code Long} object 1522 * representing this value is returned; in summary: 1523 * 1524 * <ul> 1525 * <li>If the property value begins with the two ASCII characters 1526 * {@code 0x} or the ASCII character {@code #}, not followed by 1527 * a minus sign, then the rest of it is parsed as a hexadecimal integer 1528 * exactly as for the method {@link #valueOf(java.lang.String, int)} 1529 * with radix 16. 1530 * <li>If the property value begins with the ASCII character 1531 * {@code 0} followed by another character, it is parsed as 1532 * an octal integer exactly as by the method {@link 1533 * #valueOf(java.lang.String, int)} with radix 8. 1534 * <li>Otherwise the property value is parsed as a decimal 1535 * integer exactly as by the method 1536 * {@link #valueOf(java.lang.String, int)} with radix 10. 1537 * </ul> 1538 * 1539 * <p>Note that, in every case, neither {@code L} 1540 * ({@code '\u005Cu004C'}) nor {@code l} 1541 * ({@code '\u005Cu006C'}) is permitted to appear at the end 1542 * of the property value as a type indicator, as would be 1543 * permitted in Java programming language source code. 1544 * 1545 * <p>The second argument is the default value. The default value is 1546 * returned if there is no property of the specified name, if the 1547 * property does not have the correct numeric format, or if the 1548 * specified name is empty or {@code null}. 1549 * 1550 * @param nm property name. 1551 * @param val default value. 1552 * @return the {@code Long} value of the property. 1553 * @throws SecurityException for the same reasons as 1554 * {@link System#getProperty(String) System.getProperty} 1555 * @see System#getProperty(java.lang.String) 1556 * @see System#getProperty(java.lang.String, java.lang.String) 1557 */ 1558 public static Long getLong(String nm, Long val) { 1559 String v = null; 1560 try { 1561 v = System.getProperty(nm); 1562 } catch (IllegalArgumentException | NullPointerException e) { 1563 } 1564 if (v != null) { 1565 try { 1566 return Long.decode(v); 1567 } catch (NumberFormatException e) { 1568 } 1569 } 1570 return val; 1571 } 1572 1573 /** 1574 * Compares two {@code Long} objects numerically. 1575 * 1576 * @param anotherLong the {@code Long} to be compared. 1577 * @return the value {@code 0} if this {@code Long} is 1578 * equal to the argument {@code Long}; a value less than 1579 * {@code 0} if this {@code Long} is numerically less 1580 * than the argument {@code Long}; and a value greater 1581 * than {@code 0} if this {@code Long} is numerically 1582 * greater than the argument {@code Long} (signed 1583 * comparison). 1584 * @since 1.2 1585 */ 1586 public int compareTo(Long anotherLong) { 1587 return compare(this.value, anotherLong.value); 1588 } 1589 1590 /** 1591 * Compares two {@code long} values numerically. 1592 * The value returned is identical to what would be returned by: 1593 * <pre> 1594 * Long.valueOf(x).compareTo(Long.valueOf(y)) 1595 * </pre> 1596 * 1597 * @param x the first {@code long} to compare 1598 * @param y the second {@code long} to compare 1599 * @return the value {@code 0} if {@code x == y}; 1600 * a value less than {@code 0} if {@code x < y}; and 1601 * a value greater than {@code 0} if {@code x > y} 1602 * @since 1.7 1603 */ 1604 public static int compare(long x, long y) { 1605 return (x < y) ? -1 : ((x == y) ? 0 : 1); 1606 } 1607 1608 /** 1609 * Compares two {@code long} values numerically treating the values 1610 * as unsigned. 1611 * 1612 * @param x the first {@code long} to compare 1613 * @param y the second {@code long} to compare 1614 * @return the value {@code 0} if {@code x == y}; a value less 1615 * than {@code 0} if {@code x < y} as unsigned values; and 1616 * a value greater than {@code 0} if {@code x > y} as 1617 * unsigned values 1618 * @since 1.8 1619 */ 1620 public static int compareUnsigned(long x, long y) { 1621 return compare(x + MIN_VALUE, y + MIN_VALUE); 1622 } 1623 1624 1625 /** 1626 * Returns the unsigned quotient of dividing the first argument by 1627 * the second where each argument and the result is interpreted as 1628 * an unsigned value. 1629 * 1630 * <p>Note that in two's complement arithmetic, the three other 1631 * basic arithmetic operations of add, subtract, and multiply are 1632 * bit-wise identical if the two operands are regarded as both 1633 * being signed or both being unsigned. Therefore separate {@code 1634 * addUnsigned}, etc. methods are not provided. 1635 * 1636 * @param dividend the value to be divided 1637 * @param divisor the value doing the dividing 1638 * @return the unsigned quotient of the first argument divided by 1639 * the second argument 1640 * @see #remainderUnsigned 1641 * @since 1.8 1642 */ 1643 public static long divideUnsigned(long dividend, long divisor) { 1644 if (divisor < 0L) { // signed comparison 1645 // Answer must be 0 or 1 depending on relative magnitude 1646 // of dividend and divisor. 1647 return (compareUnsigned(dividend, divisor)) < 0 ? 0L :1L; 1648 } 1649 1650 if (dividend > 0) // Both inputs non-negative 1651 return dividend/divisor; 1652 else { 1653 /* 1654 * For simple code, leveraging BigInteger. Longer and faster 1655 * code written directly in terms of operations on longs is 1656 * possible; see "Hacker's Delight" for divide and remainder 1657 * algorithms. 1658 */ 1659 return toUnsignedBigInteger(dividend). 1660 divide(toUnsignedBigInteger(divisor)).longValue(); 1661 } 1662 } 1663 1664 /** 1665 * Returns the unsigned remainder from dividing the first argument 1666 * by the second where each argument and the result is interpreted 1667 * as an unsigned value. 1668 * 1669 * @param dividend the value to be divided 1670 * @param divisor the value doing the dividing 1671 * @return the unsigned remainder of the first argument divided by 1672 * the second argument 1673 * @see #divideUnsigned 1674 * @since 1.8 1675 */ 1676 public static long remainderUnsigned(long dividend, long divisor) { 1677 if (dividend > 0 && divisor > 0) { // signed comparisons 1678 return dividend % divisor; 1679 } else { 1680 if (compareUnsigned(dividend, divisor) < 0) // Avoid explicit check for 0 divisor 1681 return dividend; 1682 else 1683 return toUnsignedBigInteger(dividend). 1684 remainder(toUnsignedBigInteger(divisor)).longValue(); 1685 } 1686 } 1687 1688 // Bit Twiddling 1689 1690 /** 1691 * The number of bits used to represent a {@code long} value in two's 1692 * complement binary form. 1693 * 1694 * @since 1.5 1695 */ 1696 @Native public static final int SIZE = 64; 1697 1698 /** 1699 * The number of bytes used to represent a {@code long} value in two's 1700 * complement binary form. 1701 * 1702 * @since 1.8 1703 */ 1704 public static final int BYTES = SIZE / Byte.SIZE; 1705 1706 /** 1707 * Returns a {@code long} value with at most a single one-bit, in the 1708 * position of the highest-order ("leftmost") one-bit in the specified 1709 * {@code long} value. Returns zero if the specified value has no 1710 * one-bits in its two's complement binary representation, that is, if it 1711 * is equal to zero. 1712 * 1713 * @param i the value whose highest one bit is to be computed 1714 * @return a {@code long} value with a single one-bit, in the position 1715 * of the highest-order one-bit in the specified value, or zero if 1716 * the specified value is itself equal to zero. 1717 * @since 1.5 1718 */ 1719 public static long highestOneBit(long i) { 1720 return i & (MIN_VALUE >>> numberOfLeadingZeros(i)); 1721 } 1722 1723 /** 1724 * Returns a {@code long} value with at most a single one-bit, in the 1725 * position of the lowest-order ("rightmost") one-bit in the specified 1726 * {@code long} value. Returns zero if the specified value has no 1727 * one-bits in its two's complement binary representation, that is, if it 1728 * is equal to zero. 1729 * 1730 * @param i the value whose lowest one bit is to be computed 1731 * @return a {@code long} value with a single one-bit, in the position 1732 * of the lowest-order one-bit in the specified value, or zero if 1733 * the specified value is itself equal to zero. 1734 * @since 1.5 1735 */ 1736 public static long lowestOneBit(long i) { 1737 // HD, Section 2-1 1738 return i & -i; 1739 } 1740 1741 /** 1742 * Returns the number of zero bits preceding the highest-order 1743 * ("leftmost") one-bit in the two's complement binary representation 1744 * of the specified {@code long} value. Returns 64 if the 1745 * specified value has no one-bits in its two's complement representation, 1746 * in other words if it is equal to zero. 1747 * 1748 * <p>Note that this method is closely related to the logarithm base 2. 1749 * For all positive {@code long} values x: 1750 * <ul> 1751 * <li>floor(log<sub>2</sub>(x)) = {@code 63 - numberOfLeadingZeros(x)} 1752 * <li>ceil(log<sub>2</sub>(x)) = {@code 64 - numberOfLeadingZeros(x - 1)} 1753 * </ul> 1754 * 1755 * @param i the value whose number of leading zeros is to be computed 1756 * @return the number of zero bits preceding the highest-order 1757 * ("leftmost") one-bit in the two's complement binary representation 1758 * of the specified {@code long} value, or 64 if the value 1759 * is equal to zero. 1760 * @since 1.5 1761 */ 1762 @HotSpotIntrinsicCandidate 1763 public static int numberOfLeadingZeros(long i) { 1764 int x = (int)(i >>> 32); 1765 return x == 0 ? 32 + Integer.numberOfLeadingZeros((int)i) 1766 : Integer.numberOfLeadingZeros(x); 1767 } 1768 1769 /** 1770 * Returns the number of zero bits following the lowest-order ("rightmost") 1771 * one-bit in the two's complement binary representation of the specified 1772 * {@code long} value. Returns 64 if the specified value has no 1773 * one-bits in its two's complement representation, in other words if it is 1774 * equal to zero. 1775 * 1776 * @param i the value whose number of trailing zeros is to be computed 1777 * @return the number of zero bits following the lowest-order ("rightmost") 1778 * one-bit in the two's complement binary representation of the 1779 * specified {@code long} value, or 64 if the value is equal 1780 * to zero. 1781 * @since 1.5 1782 */ 1783 @HotSpotIntrinsicCandidate 1784 public static int numberOfTrailingZeros(long i) { 1785 // HD, Figure 5-14 1786 int x, y; 1787 if (i == 0) return 64; 1788 int n = 63; 1789 y = (int)i; if (y != 0) { n = n -32; x = y; } else x = (int)(i>>>32); 1790 y = x <<16; if (y != 0) { n = n -16; x = y; } 1791 y = x << 8; if (y != 0) { n = n - 8; x = y; } 1792 y = x << 4; if (y != 0) { n = n - 4; x = y; } 1793 y = x << 2; if (y != 0) { n = n - 2; x = y; } 1794 return n - ((x << 1) >>> 31); 1795 } 1796 1797 /** 1798 * Returns the number of one-bits in the two's complement binary 1799 * representation of the specified {@code long} value. This function is 1800 * sometimes referred to as the <i>population count</i>. 1801 * 1802 * @param i the value whose bits are to be counted 1803 * @return the number of one-bits in the two's complement binary 1804 * representation of the specified {@code long} value. 1805 * @since 1.5 1806 */ 1807 @HotSpotIntrinsicCandidate 1808 public static int bitCount(long i) { 1809 // HD, Figure 5-2 1810 i = i - ((i >>> 1) & 0x5555555555555555L); 1811 i = (i & 0x3333333333333333L) + ((i >>> 2) & 0x3333333333333333L); 1812 i = (i + (i >>> 4)) & 0x0f0f0f0f0f0f0f0fL; 1813 i = i + (i >>> 8); 1814 i = i + (i >>> 16); 1815 i = i + (i >>> 32); 1816 return (int)i & 0x7f; 1817 } 1818 1819 /** 1820 * Returns the value obtained by rotating the two's complement binary 1821 * representation of the specified {@code long} value left by the 1822 * specified number of bits. (Bits shifted out of the left hand, or 1823 * high-order, side reenter on the right, or low-order.) 1824 * 1825 * <p>Note that left rotation with a negative distance is equivalent to 1826 * right rotation: {@code rotateLeft(val, -distance) == rotateRight(val, 1827 * distance)}. Note also that rotation by any multiple of 64 is a 1828 * no-op, so all but the last six bits of the rotation distance can be 1829 * ignored, even if the distance is negative: {@code rotateLeft(val, 1830 * distance) == rotateLeft(val, distance & 0x3F)}. 1831 * 1832 * @param i the value whose bits are to be rotated left 1833 * @param distance the number of bit positions to rotate left 1834 * @return the value obtained by rotating the two's complement binary 1835 * representation of the specified {@code long} value left by the 1836 * specified number of bits. 1837 * @since 1.5 1838 */ 1839 public static long rotateLeft(long i, int distance) { 1840 return (i << distance) | (i >>> -distance); 1841 } 1842 1843 /** 1844 * Returns the value obtained by rotating the two's complement binary 1845 * representation of the specified {@code long} value right by the 1846 * specified number of bits. (Bits shifted out of the right hand, or 1847 * low-order, side reenter on the left, or high-order.) 1848 * 1849 * <p>Note that right rotation with a negative distance is equivalent to 1850 * left rotation: {@code rotateRight(val, -distance) == rotateLeft(val, 1851 * distance)}. Note also that rotation by any multiple of 64 is a 1852 * no-op, so all but the last six bits of the rotation distance can be 1853 * ignored, even if the distance is negative: {@code rotateRight(val, 1854 * distance) == rotateRight(val, distance & 0x3F)}. 1855 * 1856 * @param i the value whose bits are to be rotated right 1857 * @param distance the number of bit positions to rotate right 1858 * @return the value obtained by rotating the two's complement binary 1859 * representation of the specified {@code long} value right by the 1860 * specified number of bits. 1861 * @since 1.5 1862 */ 1863 public static long rotateRight(long i, int distance) { 1864 return (i >>> distance) | (i << -distance); 1865 } 1866 1867 /** 1868 * Returns the value obtained by reversing the order of the bits in the 1869 * two's complement binary representation of the specified {@code long} 1870 * value. 1871 * 1872 * @param i the value to be reversed 1873 * @return the value obtained by reversing order of the bits in the 1874 * specified {@code long} value. 1875 * @since 1.5 1876 */ 1877 public static long reverse(long i) { 1878 // HD, Figure 7-1 1879 i = (i & 0x5555555555555555L) << 1 | (i >>> 1) & 0x5555555555555555L; 1880 i = (i & 0x3333333333333333L) << 2 | (i >>> 2) & 0x3333333333333333L; 1881 i = (i & 0x0f0f0f0f0f0f0f0fL) << 4 | (i >>> 4) & 0x0f0f0f0f0f0f0f0fL; 1882 1883 return reverseBytes(i); 1884 } 1885 1886 /** 1887 * Returns the signum function of the specified {@code long} value. (The 1888 * return value is -1 if the specified value is negative; 0 if the 1889 * specified value is zero; and 1 if the specified value is positive.) 1890 * 1891 * @param i the value whose signum is to be computed 1892 * @return the signum function of the specified {@code long} value. 1893 * @since 1.5 1894 */ 1895 public static int signum(long i) { 1896 // HD, Section 2-7 1897 return (int) ((i >> 63) | (-i >>> 63)); 1898 } 1899 1900 /** 1901 * Returns the value obtained by reversing the order of the bytes in the 1902 * two's complement representation of the specified {@code long} value. 1903 * 1904 * @param i the value whose bytes are to be reversed 1905 * @return the value obtained by reversing the bytes in the specified 1906 * {@code long} value. 1907 * @since 1.5 1908 */ 1909 @HotSpotIntrinsicCandidate 1910 public static long reverseBytes(long i) { 1911 i = (i & 0x00ff00ff00ff00ffL) << 8 | (i >>> 8) & 0x00ff00ff00ff00ffL; 1912 return (i << 48) | ((i & 0xffff0000L) << 16) | 1913 ((i >>> 16) & 0xffff0000L) | (i >>> 48); 1914 } 1915 1916 /** 1917 * Adds two {@code long} values together as per the + operator. 1918 * 1919 * @param a the first operand 1920 * @param b the second operand 1921 * @return the sum of {@code a} and {@code b} 1922 * @see java.util.function.BinaryOperator 1923 * @since 1.8 1924 */ 1925 public static long sum(long a, long b) { 1926 return a + b; 1927 } 1928 1929 /** 1930 * Returns the greater of two {@code long} values 1931 * as if by calling {@link Math#max(long, long) Math.max}. 1932 * 1933 * @param a the first operand 1934 * @param b the second operand 1935 * @return the greater of {@code a} and {@code b} 1936 * @see java.util.function.BinaryOperator 1937 * @since 1.8 1938 */ 1939 public static long max(long a, long b) { 1940 return Math.max(a, b); 1941 } 1942 1943 /** 1944 * Returns the smaller of two {@code long} values 1945 * as if by calling {@link Math#min(long, long) Math.min}. 1946 * 1947 * @param a the first operand 1948 * @param b the second operand 1949 * @return the smaller of {@code a} and {@code b} 1950 * @see java.util.function.BinaryOperator 1951 * @since 1.8 1952 */ 1953 public static long min(long a, long b) { 1954 return Math.min(a, b); 1955 } 1956 1957 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 1958 @Native private static final long serialVersionUID = 4290774380558885855L; 1959 }